Word Origin & History
dub"give a name to," originally "make a knight," from O.E. dubbian "knight by striking with a sword" (11c.), a late word, perhaps borrowed from O.Fr. aduber "equip with arms, adorn," of uncertain origin.
dub"add or alter sound on film," 1929, shortening of
double; so called because it involves re-recording voices onto a soundtrack. The type of re-mixed reggae music was so called from 1974, probably for the same reason. Related: Dubbed; dubbing.